• Journal of the Korean Society for Railway
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• v.17 no.4
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• pp.251-259
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• 2014

The transition zone between an earthwork and a bridge effect to the vehicle's running stability because support stiffness of the roadbed is suddenly changed. The design criteria for the transition structure on ballast track were not particular in the past. However with the introduction of concrete track is introduced, it requires there is a higher performance level required because of maintenance and running stability. In this present paper, a transition structure reinforced with geosynthetics is suggested to improve the performance of existing bridge-earthwork transition structures. The suggested transition structure, in which there is reinforcing of the approach block using high-tension geosynthetics, has a structure similar to that of earth reinforced abutments. The utilized backfill materials are cement treated soil and gravel. These materials are used to reduce water intrusion into the approach block and to increase the recycling of surplus earth materials. An experiment was performed under the same conditions in order to allow a comparison of this new structure with the existing transition structure. Evaluation items are elastic displacement, cumulative settlement, and earth pressure. As for the results of the real-scale accelerated testing, the suggested transition structure has excellent performance for the reduction of earth pressure and settlement. Above all, it has high resistance the variation of the water content.

• Elastomers and Composites
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• v.48 no.1
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• pp.67-75
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• 2013

E-TPE (Engineering Thermoplastic Polyether Ester) was Ester Elastomer with functional groups as recycling and fast processability. In addition, if the car's lightweight enough to highlight eco-friendly materials that help to improve fuel economy has become. Have all the attributes of the rubber and engineering plastics E-TPE the available temperature area is spacious, heat resistance and oil resistance is excellent but getting attention as a new material in the field of auto parts in the field of electrical and electronic domestic depends entirely on imports by the lack of core technology and has been research and development is urgently needed. In this study, the hard segments, polyester (TPEE) as the base soft elastomers of the segments Ethylen-prophylene-Copolymer and CSM (Choloro sulphonated polyethylene Rubber), VAMAC (Ethylene Acrylic Rubber), NBR (Acrylonitrin Butadiene Rubber), 1, 3-Phenylene-bisoxazoline is dealing with Dynamic Vulcanized by content and added rubber properties, thermal variation observed. As a result, the properties of the dynamic vulcanization with NBR compared to other rubber heat resistance and oil resistance is on the increase.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.45 no.3
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• pp.69-76
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• 2008

This work proposes a 12b 1kS/s 65uA 0.35um CMOS algorithmic ADC for sensor interface applications such as accelerometers and gyro sensors requiring high resolution, ultra-low power, and small size simultaneously. The proposed ADC is based on an algorithmic architecture with recycling techniques to optimize sampling rate, resolution, chip area, and power consumption. Two versions of ADCs are fabricated with a conventional open-loop sampling scheme and a closed-loop sampling scheme to investigate the effects of offset and 1/f noise during dynamic operation. Switched bias power-reduction techniques and bias circuit sharing reduce the power consumption of amplifiers in the SHA and MDAC. The current and voltage references are implemented on chip with optional of-chip voltage references for low-power SoC applications. The prototype ADC in a 0.35um 2P4M CMOS technology demonstrates a measured DNL and INL within 0.78LSB and 2.24LSB, and shows a maximum SNDR and SFDR of 60dB and 70dB in versionl, and 63dB and 75dB in version2 at 1kS/s. The versionl and version2 ADCs with an active die area of $0.78mm^2$ and $0.81mm^2$ consume 0.163mW and 0.176mW at 1kS/s and 2.5V, respectively.

• Land and Housing Review
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• v.1 no.1
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• pp.35-42
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• 2010

Most of the dredged sand generated from the sewage pipe maintenance project and the government's four-river project are disposed depending on abandonment and filling-up. This is caused by the lack of related recycling technology using dredged sand appropriately and high absorption rate and micro-particles of dredged sand producted from existing sand production system. Thus, this study carried out a quality assessment for the dredged sand produced through the optimum washing and sorting system supplementing problems of existing dredged sand production system as a part of research to examine performance of removing micro-particles and foreign substances. As a result of the assessment, the dredged sand produced through the cleaning and sorting system showed a wide quality improvement effect in absorption rate, 0.08 mm sieve pass amount, clay lump volume and organic impurity content, and it turned out to satisfy both the quality standards of this study, KS F 2573(recycled aggregate for concrete) and KS F 2526(aggregate for concrete) so it could be confirmed that it would be able to be used as an aggregate for concrete in the future.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.2
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• pp.99-105
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• 2010

This paper investigated the characteristics of wasteform containing a spent zeolite used as a separating agent of FPs for recycling LiCl waste which would be generated from pyrochemical process of spent PWR fuel. In this study, a conventional borosilicate and Ca-rich glass were used as a consolidating agent for spent zeolite and it's mixing ratio was changed in the range, $25{\sim}35wt%$. The leach rates of Cs and Sr had about $0.1{\sim}0.01g/m^2day$ and $0.001{\sim}0.0001g/m^2day$, respectively. The leach resistance of Cs increased with amount of SAP and it showed about 10 times higher in the Ca-rich glass wasteform than in the conventional borosilciate glass wasteform. The compressive strength of wasteform was affected with the amount of glass. Thermal expansion rate of containing 30wt% glass has relatively lower than others. Also, the melting temperature was little changed in given mixing ratio of glass.

• Korean Journal of Materials Research
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• v.6 no.8
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• pp.761-767
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• 1996

The composite fiber adsorbents containing amidoxime group were prepared and separation properties of uranium ion from seawater were investigated. The amount of uranium adsorption was increased with an increase in adsorption time. When the mole ratio of monomer and comonomer, such as acrylonitrile (AN), tetraethyleneglycol dimethacrylate(TEGMA), and divinylbenzene (DVB), were 1 :0. 1 :0.003, this resin showed the maximum adsorption ability for uranium at a level of pH 8. The amount of uranium adsorption was also increased linearly to one hour with an increase in the content of adsorbent which was added in the composite fiber adsorbents(CFA). The maximum adsorption for uranium of CF A showed at $25^{\circ}C$. Hence, the adsorption ability of CF A for calcium and magnecium ions were increased gradually by the recycling of adsorption and disorption, the adsorption content of their on were 0.3, 0.9mmole/g-adsorbents, respectly. It also showed that the adsorption contents of Ca and \1g ions were much lower than them of uranium. The desorption of uranium on the CF A was carried out , bout 100% within 30min, and the desorption rate of various CF A were equalled.

• Herbal Formula Science
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• v.29 no.4
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• pp.239-252
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• 2021

Objectives : This study is to effect of improving muscle atrophy through water extract on the solid-phase fermentation extraction with Phellinus linteus of discarded Schisandra chinensis in an atorvastatin-induced atrophy C2C12 cell. Methods : C2C12 myoblast were differentiated into myotube by 2% horse serum medium for 6 days, and then treated solid-phase fermentation(S-P) extract at different concentrations for 24h. To investigate the effect of S-P extract on the induction of muscle atrophy and expression of atrophy-related genes and apoptosis in differentiated C2C12 myotubes using a GSH, ROS, real-time PCR, western blots analysis. Results : As a result of treatment with atorvastatin at concentrations of 5, 10, and 20 uM on the 6th day of differentiation in C2C12 myotube cells, it was confirmed that the cell morphology was damaged in a concentration-dependent manner, and the length and thickness of the myotube also decreased in a concentration-dependent manner. Treatment with S-P extract (50, 100 and 200 ㎍/㎖) increased of GSH and inhibited ROS in the atorvastatin-induced muscle atrophy cell model at a concentration that did not induce toxicity. In addition, it was confirmed that it has an effect on muscle reduction by inhibiting apoptosis of muscle cells as well as being involved in protein production and degradation of muscle cells. Conclusions : Atorvastatin-induced atrophy C2C12 cell, S-P extract activates related to differentiation/generation and proteolysis, and inhibits cell death of atrophy in C2C12 cell. Based on this, it is necessary to prove its effectiveness through animal models and human application test, but it is considered to be discarded Schisandra chinensis can present the potential for development as a recycling industrial material.

• Journal of Adhesion and Interface
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• v.22 no.1
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• pp.1-7
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• 2021

The importance of high capacity energy storage devices has recently emerged for stable power supply through renewable energy generation. From this point of view, the Na-air battery (NAB), which is a next-generation secondary battery, is receiving huge attention because it can realize a high capacity through abundant and inexpensive raw materials. In this study, activated carbon-based catalysts for hybrid type Na-air batteries were prepared and their characteristics were compared and analysed. In particular, from the viewpoint of resource recycling, activated carbon (Orange-C) was prepared using discarded orange peel, and performance was compared with Vulcan carbon, which is widely used. In addition, a Pt/C catalyst (homemade-Pt/C, HM-Pt/C) was synthesized using a modified polyol method to check whether the prepared activated carbon can be used as a supported catalyst, and a commercial Pt/C catalyst (Commercial Pt/C) and electrochemical performance were compared. The prepared Orange-C exhibited a typical H3 type BET isotherm, which is evidence that micropore and mesopore exist. In addition, in the case of HM-Pt/C, it was confirmed through TEM analysis that Pt particles were evenly distributed on the activated carbon supported catalyst. In particular, the HM-Pt/C-based NAB showed the smallest voltage gap (0.224V) and good voltage efficiency (92.34%) in the 1st galvanostatic charge-discharge test. In addition, the cycle performance test conducted for 20 cycles showed the most stable performance.

• Journal of Korea Society of Waste Management
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• v.35 no.7
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• pp.616-626
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• 2018

The quality standards of solid refuse fuel (SRF) define the values for 12 physico-chemical properties, including moisture, lower heating value, and metal compounds, according to Article 20 of the Enforcement Rules of the Act on Resource Saving and Recycling Promotion. These parameters are evaluated via various SRF Quality Test Methods, but problems related to the heavy metal content have been observed in the microwave acid digestion method. Therefore, these methods and their applicability need improvement. In this study, the appropriate testing conditions were derived by varying the parameters of microwave acid digestion, such as microwave power and pre-treatment time. The pre-treatment of SRF as a function of the microwave power revealed an incomplete decomposition of the sample at 600 W, and the heavy metal content analysis was difficult to perform under 9 mL of nitric acid and 3 mL of hydrochloric acid. The experiments with the reference materials under nitric acid at 600 W lasted 30 minutes, and 1,000 W for 20 or 30 minutes were considered optimal conditions. The results confirmed that a mixture of SRF and an acid would take about 20 minutes to reach $180^{\circ}C$, requiring at least 30 minutes of pre-treatment. The accuracy was within 30% of the standard deviation, with a precision of 70 ~ 130% of the heavy metal recovery rate. By applying these conditions to SRF, the results for each condition were not significantly different and the heavy metal standards for As, Pb, Cd, and Cr were satisfied.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.71-77
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• 2022

To increase biomass utilization, rice husk-based activated carbon (RHAC) followed by nitrogen plasma surface treatment was prepared and the electric double-layer capacitor performance was investigated. Through nitrogen plasma surface treatment, up to 2.17% of nitrogen was introduced to the surface of RHAC, and in particular the sample reacted for 5 min with nitrogen plasma showed dominant formation of pyrrolic/pyridine N functional groups. In addition, mesopores were formed on the RHAC material by the removal of silica, and the surface roughness of the carbon material increased by nitrogen plasma surface treatment, resulting in the formation of many micropores. As a result of cyclic voltammetry measurement, at a scan rate of 5 mV/s, the specific capacitance of the RHAC treated with nitrogen plasma increased up to 200 F/g, showing an 80.2% improvement compared to that of using untreated RHAC (111 F/g). This is attributed to the synergetic effect of the introduction of pyrrolic/pyridine-based nitrogen functional groups and the increase of the micropore volume on the surface of the carbon material. This study has a positive effect on the environment in terms of recycling waste resources and using plasma surface treatment.